Rubber article and method for making the same



Feb. 10, 1942. c. L. BEAL. 2,272,290

RUBBER ARTICLE AND METHOD OF MAKING THE SAME Filed Aug. 26, 1937 mm* 1-ff Z5-5% 7 aillluw z Patented Feb. 1o,` 1942 RUBBER ARTICLE AND METHODFOR MAKING THE SAME Carl L. Beal, Cuyahoga Falls, Ohio, assignor toAmerican Anode, Inc., Akron, hio, a corporation of Delaware ApplicationAugust 26, 1931, serial No. 161,054

19 claims. (ci. 11a-ess)v This invention relates to the manufacture ofrubber articles and especially to the manufacture of inflatable hollowrubber articles such as pneumatic cushions having opposed walls locallyconnected between the margins to prevent undue distension of the cushionupon inflation, and in which the local connecting means between theopposed walls preferably take-the form of tubes providing Ventilatingopenings through the cushion. v

It is highly desirable that articles of the character described shouldhave an integral continuous rubber structure, especially in thecushioning zone, to provide maximumstrength and durability, butconventional methods of manufacture cannot be used to produce sucharticles in integral form because the connections between the facesprevent removal of the mandrel or form which ordinarily is required inmaking integral hollow articles. to use a destructible mandrel or formsuch as a paper form for such purposes, but the destruction of the formand the removal of the residue is a tedious and costly job and anoperator can rarely be certain that all the destroyed form has beenremoved so that portions frequently are left within the cushion withundesirable consequences. Furthermore, the cost of a new form for eacharticle made is not an inconsequential item. In my copending applicationSerial No.

It has been proposedl 115,240, filed December 10,-1936, which now has fmatured into U. S. Patent No. 2,272,289, granted concurrently herewithon February 10, 1942, I havedescribed the use of a sectional metal formfor making apertured pneumatic cushions and the like, and while thisexpedient has proved to be lquite satisfactory, it'is open to theobjection that the rubber usually must be stretched somewhat while stillunvulcanized to permit removal of the form sections, which in some caseshas resulted in undesirable distortion of the incomplete cushion.

The present invention accordingly has for its objects the provision of asimple, economical and efcient method for making apertured and tufted"hollow rubber cushions with an integral continuous rubber structure; toprovide a novel deposition form for use in such method; to pro'- videnovel and dependable constructions in hollow rubber articles` such asapertured and tufted cushions and generally to provide economy andefficiency in the manufacture of rubber articles.

The manner in which these and other objects of the invention areachieved will be evident from the following description of the inventionas illustrated in the accompanying drawing, of which Fig.,1 is asectional elevation showing a deposiof Fig. 1;

Fig. 3 is an elevation showing the rubber coating being stripped fromthe form of Fig. 1;

Fig. 4 is an elevation, partially sectioned for clarity of illustration,showing an intermediate step in the process;

Fig. 5 is a fragmentary vertical section of the intermediate productproduced by the operation illustrated in Fig. 4;

Fig. 6 is a vertical section illustrating a fur-l ther step in theprocess and showing the intermediate product immersed in a liquid rubbercomposition;

Fig. 7 is a fragmentary vertical section of the nal product.

Fig. 8 is a fragmentary vertical section of a nal product made by aslightly different procedure embodying the present invention in amodified form.

In the preferred method vof the present invention, I use a depositionform I0 of, for example, generally rectangular, planar configurationprovided with a supporting handle II, and formed of a suitablenon-corrodible metal such as aluminum. A number of circular depressionsI2, I2, preferably are provided in each face of theplanar form I0, thedepressions being suitably spaced apart in opposed pairs with a portionof the form'material remaining to form a thin wall I3 between thebottoms of opposed depressions of each pair as more clearly shown inFig. 2.

In the process, the form .I0 is immersed in a liquid rubber compositionI4 contained in a tank I5, and an enveloping coating of rubber isdeposited upon the form in any well known manner. Preferably however,the liquid rubber composition Il should be an aqueous dispersion ofunvulcanized rubber such as natural rubber latexv compounded with theusual vulcanizing and conytion form immersed in a liquid rubbercomposiditioning ingredients, in which case, the form I0 mayadvantageously be coated with a coagulant for the aqueous dispersion andalso with a pulverulent separating materiales described in U. S. PatentNo. 1,924,214 to expedite deposition of the rubbercoatingand tofacilitate stripping the coating from the form.

After the deposited rubber coating has been dried sumciently to permithandling, but before it is vulcanized, a slit is made along one edge ofthe coating' to permit stripping the coating from the form as shown inFig. 3, thereby to produce 'a fiat rubber bag I6 having opposeddepressions molded in its walls corresponding to the depressions I2, I2in the form III.

The bottoms of the depressions in the rubber bag I6 are then died outand the adjacent edges of the opposed rubber bag walls aresimultaneously cut-seamed by means of conventional clicking dies I1, I'Ioperating against cooperating anvils I8, I8 to produce a. baghavingapertures therein as shown in Fig. 5.

To reenforce the cutseamed edges at the apertures, and to insure anintegral, one-piece, continuous and therefore thoroughly dependableconstruction, the bag i6 is then preferably immersed in the liquidrubber composition i4, as shown in Fig. 6, one or more times to deposita second enveloping coating of rubber i9 over all portions of the bagthereby to provide a seamless structure at the apertures and at the sametime to seal the slit which was previously made in the edge of the bagIt. Desirably, although not necessari1y,' the edges of the slit may belocally coated 4with a solvent solution of rubber commonly called arubber cement, prior to application of the nal sealing coating ofrubber, in order to secure most satisfactory sealing. In some cases, thenal enveloping coating of rubber may be omitted, the unreenfor'cedcut-seam having suiiicient strength, after vulcanization, to withstandconsiderable service. Or in another modification, a local reenforcingdepositv or strip of rubber may be applied to the cut-seams as bybrushing latex thereon.

To complete the cushion, the rubber is vulcanized and a conventionalinflating valve is provided at any desired location, all according tousual practice and requiring no detailed explanation.

In a slightly modied procedure which may advantageously be used formaking relatively thin cushions, I may use a plane deposition formwithout depressions, and produce in the manner described a rubber baghaving smooth faces, then die out openings in the two faces andsimultaneously cut-seam the adjacent edges, and apply an overallenveloping coating of rubber to produce an integral structure as before.If the openings died out in either process are small, for example, about0.25 inch in diameter or less, and no preventive precautions are taken,the liquid rubber composition will web over the openings when the nalcoating of rubber is applied. especially when using an aqueousdispersion of rubber, and will produce webs closing the apertures in thecushion. A cushion made by such a modied procedure is illustrated inFig. 8 in which the numeral 2| indicates the initial rubber bag made ona smooth fonnin which openings have been died and the edges cut-seamedat 22, 22, and the bag then immersed in latex one or more times to applya second enveloping coating of rubber 23, and in which the latex haswebbed over the apertures to produce webs 24, 24. When such a cushion isinated, it will assume a tufted appearance, rather than the aperturedappearance of the cushion of Fig. 7.

For clarity of illustration, the two coats of rubber, designated by thenumerals I and Il in the first example and by the numerals 2| and 23 inthe second example, have been shown as two separate distinct vlayers ofrubber, but it is to be understood that upon vulcanization, the twolayers merge and blend into an integral body of rubber, although thecut-seams will still be evident.

By the procedures described I am able to produce, with minimum expense,inatable hollow cushions provided with any desired number of distensionlimiting connections between the cushion faces, either in the form oftubes providing ventilation for the cushion, or in the form ofdepressions terminating in a web and producing tufts and to insure ineither type cushion an integral continuous rubber structure providingmaximum strength and durability. The invention therefore attains to ahigh degree the objects set forth. l

.Numerous modifications and variations in details of the procedure asherein described may be made without departing from the spirit and scopeof the invention as dened by the appended claims.

I claim:

l. The method of making a rubber article having opposed walls integrallyconnected between the margins of the article, which comprises bringingtogether two sheets of unvulcanized rubber adapted to constitute opposedfaces of the finished article, cut-seeming the two sheets together at apoint between the margins thereof, applying a coating of a liquid rubbercomposition to the cut-seam and contiguous areas, solidifying the liquidrubber composition to produce a. sealing coating of rubber, andvulcanizing the rubber.

2. The method of making a hollow rubber article having opposed wallsintegrally connected between the margins of the article, which comprisesproducing a. rubber bag having two opposed walls and an opening in thebag, cut seaming the walls together at a point spaced from said openingand between the margins of the walls, coating substantially the entirebag with a liquid rubber composition and solidfying the liquidcomposition to produce a coating of rubber sealing the opening in thebag and reenforcing the cut-seam.

3. The method of making a hollow rubber article having opposed wallsintegrally connected between the margins ofthe article, which comprisesproducing a rubber bag 'having two opposed walls and an opening at amargin of the bag, cutting aligned localized portions from the two wallsand simultaneously cut-seaming the adjacent edges, and applying asealing coating of rubber to portions of the bag including the cut-seamand the opening in the bag.

4. The method ,of making a hollow rubber article having opposedwallsintegrally connected between the margins of the article, whichcomprises producing a rubber bag having a wall with a molded depressiontherein and a second wall opposed to the rst wall, cutting one openingin f. the depression wall and a second opening in an aligned portion ofthe opposed wall and simul taneously cut-seeming the rubber at the cutedges of the two walls.

5. The method of making a hollow rubber article having opposed wallsintegrally connected between the margins of the article, which comprisesproducing a rubber bag having a wall with a molded depression thereinand a second wall opposed to the first wall,'cutting one opening in thedepression wall, a second opening in an aligned portion of the opposedWall and slmultaneously cut-seaming`the rubber at the out edges of thetwo walls.. and applying a sealing coating of rubber to the cut-seam andcontiguous areas.

6. The method of making a hollow rubber article having opposed wallsintegrally connected between the margins of the article, which comprisesproducing a rubber bag having opposed walls provided with opposed moldeddepressions. cutting openings in the opposed depressions andsimultaneously cut-seaming the rubber at the cut edges of the two walls.

7. The method of making a hollow rubber article having opposed wallsintegrally connected between the margins of the article, which comprisesproducing a rubber bag having opposed walls provided with opposed moldeddepressions, cutting openings in the opposed depressions andsimultaneously cut-seaming the rubber at the cut edges of the two walls,and applying a sealing coating of rubber to the cut-seam and contiguousareas.

8. The method of making an inatable hollow rubber article having opposedwalls integrally connected between the margins of the article, whichcomprises providing a deposition form having the general shape of thedesired article, producing upon the form an enveloping coating ofrubber, slitting the rubber coat, removing the form through the slit,cut-seaming opposed portions of the coating together'at a point betweenthe margins thereof, applying a liquid rubber composition to thecut-seam and to the slit and solidifying the liquid rubber composition.

9. The method of making a hollow rubber article having opposed wallsintegrally connected between the margins of the article, which comprisesproviding a deposition form having a depression where the integralconnection is desired in the rubber article, producing, by depositionfrom a liquid rubber composition, upon the form including the depressiona coating of rubber having a wall with a molded depression and anopposed wall, stripping the rubber from the form, cutting an opening inthe wall depression and in anA aligned portion of the opposed wall andsimultaneously cut-seaming the rubber at the cut edges.

10. The method of making a hollow rubber article having opposed wallsintegrally connected between the margins of the article, which comprisesproviding a deposition form having opposed depressions in two facesthereof where the integral connection is desired in the rubber article,depositing rubber from a liquid rubber composition upon the form toproduce thereon a coating of rubber constituting a bag having opposedmolded depressions in the walls thereof, stripping the bag from theform, cutting openings in the opposed depressions and simultaneouslycut-seaming the rubber at the cut-edges.

11. The method of making an iniiatable hollow rubberartiole havingopposed walls integrally connected between the margins of the article,which comprises providing a deposition form having opposed depressionsin the faces thereof where the integral connection is desired in therubber article, depositing rubber from a liquid rubber composition uponthe form to produce thereon an enveloping coating of rubber having facesprovided with opposed molded depressions, slitting the coating, removingthe form through the slit, cutting openings in the opposed depressionsin the rubber and simultaneously cut-seaming the rubber at thecut-edges, applying a liquid rubber composition to the cutseam and tothe slit, and solidifying` the liquid rubber composition.

12. The method of making an infiatable hollow rubber article havingopposed walls integrally connected between the margins of the article,which comprises providing a deposition form having opposed depressionsin the faces thereof where the integral connection is desired in therubber article, depositing rubber from a liquid composition upon theform to produce thereon an enveloping coating of rubber, slitting thecoating, removing the form through the slit, cutting openings in tbeopposed depressions and simultaneously out-seaming the rubber et the cutedges, immersingthe entire article in a liquid rubber composition andsolidifying the composition to form a sealing deposit of rubber.

13. The method of making a tufted hollow rubber article which comprisesproducing a hollow article having opposed walls, cutting small alignedopenings in the opposed walls and simultaneously cut-seaming the rubberat the cut edges, immersing the article in a liquid rubber compositionwhich will web over the small openings, and drying the resulting rubbercoating and webs.

14. The method of making a hollow rubber article of complicatedstructure preventing removal of a form from the finished article, whichcomprises providing a form designed to produce the general hollowstructure but not the obstructing portions of the final article,producing a deposit of rubber upon the form, removing the deposit fromthe form, cutting and seaming the deposit to produce the desiredstructure, and immersing the deposit in a liquid rubber composition toproduce a sealing and reenforcing coating of rubber thereon.

15. A hollow rubber article fhaving opposed walls integrally connectedbetween the margins of the article, comprising a hollow body of rubberhaving opposed walls locally cut-seamed at a point between the marginsthereof and a seamless coating of rubber overlying the cutseam andadiacent areas and being integrally bonded to the said body of rubber.

16. A hollow rubber article having opposed walls integrally` connectedbetween the margins of the article, comprising a hollow body of rubberhaving opposed walls locally cut-seamed at a point between the marginsthereof, and a seamless coating of rubber enveloping the said body andbeing integrally bonded thereto.

17. A hollow rubber article comprising opposed sheet faces joined by atleast one tubular connector disposed betweenthe margins of the article,the structure of said article being essentially integral and presentinga seamless exterior surface in the region of the tubular connector, thestructure comprising inner walls cut-seemed together in the region ofthe tubular connector and an outer wall comprising a seamless coating ofrubber overlying the cut-seam and adjacent areas and being integrallybonded to the rubber of the inner walls.

18. The method of vmaking 'a hollow rubber article comprising opposedsheet ,faces joined by at least one tubular connector disposed betweenthe margins of the article, which comprises producing a rubber baghaving opposed sheet Walls, cut-seaming the opposed walls together alonga generally circular line and simultaneously severing wall material fromboth walls within the circular line to form a tubular connector.betweenv the walls, and coating at least a portion of the tubularconnector including the cut-seam and adjacent areas with a liquid rubbercomposition and solldifylng the composition.

19. The methodiof making a rubber article which comprises forming twoportions of the article by depositing rubber from a liquid rubbercomposition, cut-seaming the two portions together in a determinatezone, coating at least a substantial part of said zone including thecutseam with a liquid rubber composition, 'and solidifylng thecomposition to form an adherent coating overlying the out-seam.

,5m L DEAL.

